1. Field of the Invention
This invention relates to an induction stirrer/mold assembly for a continuous casting apparatus, and more particularly to improvements in induction stirrer/mold assembly useful for stirring molten metal in a mold by electromagnetic hydrodynamic action.
2. Description of the Prior Art
In the continuous casting process, it is known to employ an induction stirrer/mold assembly incorporating electromagnetic inductors around a mold to produce rotating or moving magnetic fields, thereby rotating the molten metal which flows into the mold for the purpose of facilitating accelerated flotation and separation of non-metallic inclusions and adjusting the solidified structure in the cast stock for improvement of internal segregations.
Mold assemblies of this sort are described, for example, in French Pat. Nos. 2,238,564 and 2,315,344, in which a tubular jacket of a non-magnetic material is placed in a space defined within a tubular element of copper or copper alloy and a tubular outer casing positioned concentrically with the tubular element and connected to the tubular element by a lid and a bottom plate each with an opening of a shape corresponding to the sectional shape of the tubular element. Electromagnetic inductors are mounted within the tubular jacket in such a manner as to form a number of predetermined cooling water passages. Since the electromagnetic inductors of a mold of this type are immersed in cooling water, it becomes necessary to disassemble and reassemble the mold off line for replacement when the tubular element of copper or copper alloy or the mold wall has worn out as a result of casting operation over a certain time period. In order to maintain satisfactory productivity and efficiency of continuous casting equipments, the demands for mold replacement must be immediately Fulfilled by providing a number of spare molds corresponding to that of the molds which are in service. However, a large equipment cost is incurred--; since electromagnetic inductors with the required properties are extremely expensive.
Further, the mold replacement technique takes a long time for disconnecting and connecting large power cables which are required for the electromagnetic inductors for supply thereto of a large current oftentimes as high as several hundreds to several thousands of amperes. In a case where the mold assembly employs separate cooling systems, one for cooling the mold itself and the other for preventing heat generation of the electromagnetic inductors, mold replacement technique takes a longer time for disconnecting and connecting the pipes of these cooling systems.